Rove McManus took awkward jokes to a new level when he made a listener grab a waiter's butt while her horrified mum watched on.

As part of his "Say Hi To Your Mum For Me" segment on Rove & Sam for breakfast on Hit 104.1 2DayFM, the 42-year-old comedian gave listener Annika a challenge to totally freak out her unsuspecting mum Marion…and she nailed it.

Controlling the conversation through a secret earpiece, he instructed the 25-year-old to speak in a French accent, tell strangers to kiss her dog, yell loudly and…umm…get totally inappropriate with a waiter.

"That's sexual harassment in the work place," Marion exclaimed as her daughter reached out and grabbed the man's bum, encouraging her to also cop a feel. You got that right, mum! Let's just hope the waiter was in on the joke.

After eventually revealing himself, Rove gave the star-struck Sydney mum permission to grab his own butt.